In Situ Exsolved Co‐BaO‐La 2 O 3 Interface from Barium‐Doped Perovskites for Catalyzing Ammonia Decomposition Reaction

Ammonia decomposition is a key route for CO x ‐free hydrogen production and nitrogen recycling, which requires efficient and durable catalysts. Non‐noble metal catalysts are attractive because of their low cost and availability. However, low activity and poor stability caused by particle sintering hinder practical applications. Constructing an efficient ternary metal‐promoter‐support interface offers a viable strategy to overcome these limitations. Herein, an in situ exsolution method was employed to fabricate Co‐Ba/La 2 O 3 catalyst from high‐purity perovskite precursor La 0.95 Ba 0.05 CoO 3 under reaction conditions. The efficient Co‐BaO‐La 2 O 3 interface was constructed via Ba‐promoted in situ exsolution process, outperforming that prepared by traditional methods and enhancing catalytic performance. The optimized catalyst achieves a high hydrogen production rate of 98.5 mmol H 2 g cat −1 h −1 at 500°C, surpassing most reported Co‐based catalysts, and exhibits excellent catalytic stability during the 200 h test. The superior performance originates from the unique interfacial structure with dispersed and anchored Co nanoparticles, which thereby strengthen metal–support interactions. The Ba promoter enhances interfacial charge transfer efficiency and catalyst basicity. This synergistic interface effectively facilitates nitrogen associative desorption and suppresses hydrogen poisoning. This work demonstrates that constructing an efficient exsolved interface can alleviate the activity‐stability conflict, offering a new strategy for designing advanced non‐noble metal catalysts.